Counterbalancing mechanism



May 21, 1957 w. YOUNG 9 I COUNTERBALANCING MECHANISM Filed Nov. 18, 19543 Sheets-Sheet l 1L2 Hazy, dCCeaaewZ g IYZDMZZflE-zecwtz ir,

May 21, 1957 r w. YOU NG 2,792,589

COUNTERBALANCING MECHANISM 3 Shee ts-Sheet 2 Filed Nov. 18. 1954 3SheetS-Sheet 3 EUcizztaE W. YOU NG COUNTERBALANCING MECHANISM May 21,1957 I Filed Nov. 18, 1954 Tired States Patent 2,792,589COUNTERBALANCING MECHANISM Application November 18, 1954, Serial No.469,765 1 Claim. (Cl. 16-201) William Young, deceased,

This invention has reference to counter-balancing mechanism forvertically sliding windows and particularly to constant balancingmechanism of the type comprising a transverse spindle with helicalscroll or thread and which is rotated on the opening and closing of thewindow, a traveller member mounted thereon and co-operating with thescroll or thread so that it will be moved laterally when the spindle isrotated, and a helical compression spring which acts on the travellermember so that the latter exerts a torque on the spindle, the scroll orthread having a pitch which increases from one end to the other so thatthe torque transmitted to the spindle remains substantially constantirrespective of the position of the window.

Heretofore, in window balance kind set forth it has mechanism of thebeen the practice to make the necessary adjustment in the spring beforefitting the mechanism to the window. With this procedure however it isdifficult to obtain such adjustment which will most efiectively balancethe window.

The present invention has therefore for its object to provide animproved mechanism of the kind set forth which can be fitted to a windowwithout adjustment and adjustment thereafter effected in a simple andetfective manner, the adjustment so obtained being such as will mosteffectively counter-balance the window.

A preferred embodiment of the invention will now be described by way ofexample with reference to the annexed drawings which show the improvedbalance mech- 'anism applied to a half-drop window. In the drawings,

Figure 1 is an elevation of a half-drop window with balance mechanism inaccordance with the invention;

Figure 2 is a section on the line 2-2 of Figure 1;

Figure 3 is a sectional elevation of the improved counter-balancingmechanism;

Figure 4 shows one end of the improved counterbalancing mechanism;

Figure 5 is a section on the line 5-5 of Figure 4;

Figure 6 is a section on the line 6-6 of Figure 3 and Figure 7 is asection on the line 7-7 of Figure 3.

As shown in the drawings the half-drop window comprises a fixed outerframe a the bottom half of which is glazed with a fixed pane b. Slidablevertically in the fixed frame is a top half glazed frame arranged tomove approximately half the depth of the fixed outside frame.

On the middle of the fixed frame a transverse tubular casing d is firmlyattached and in this tubular casing is fitted a spindle e having ahelical scroll or thread e Moounted on said scroll is a travellermember 1. The cross section of the casing and the traveller member isnon-circular as shown in Figure 7 so that when the spindle is rotatedthe said traveller member f can travel laterally thereon but cannotrotate.

One end of the spindle g which meshes with one of a h]. having anenclosing casing j longitudinally-sliding locking has fast thereon apinion wheel pair of vertical racks h and with slot in which is fitted akey k, the end k of which secured to the top half glazed frame 0, saidwheel ,5 8 9 Patented May 21, 1957 ice . 2 is arranged to engage withthe wheel therein by fitting in the gap between adjacent teeth. Theother end of the spindle has fitted loosely thereon one member I of adog clutch. This member is provided with a series of holes I which canbe brought into register with an axial slot m in the tubular casing d.

The other member 11 of the dog clutch is integral with or has securedthereto the other pinion wheel 0 which latter is likewise enclosedwithin a casing p secured to the fixed frame. The pinion wheel 0 mesheswith the other rack h The helical scroll or thread is encircled by ahelical compression spring q one end of which is anchored to thenon-rotatable traveller member 7 and the other to the dog clutch memberI, said spring normally holding the clutch members in engagement witheach other.

The pitch of the helical scroll or thread is not uniform but increasesas it approaches the end carrying the clutch.

When the top half glazed frame 0 is being raised and lowered the twopinion wheels g and 0 will be rotated by meshing with the racks h and hand in consequence the spindle e with scroll or helical thread willlikewise be rotated. The traveller member 1 mounted thereon, beingincapable of rotation, will travel transversely to the left or to theright as the case may be and in doing so will increase or decrease,according to its direction of movement, both the compression and thetorsion of the spring q. The force of the spring acting on the travellermember f imparts a torque to the spindle which tends to rotate thepinion wheels so that they will oppose the downward movement of thewindow. The torsion of the spring tends to rotate the spindle in thesame direction so that the compression and torsion of the spring combineto impart a torque to the spindle tending to oppose the downwardmovement of the window. The pitch of the helical scroll or thread is sovaried that the torque due to the compression and torsion of the springis substantially uniform so that in all positions of the sliding windowthe latter is balanced.

In fitting the window it is necessary to regulate the torque imparted bythe spring and also it may be necessary to subsequently adjust saidtorque.

Assume it is desired to impart to or increase the torque in the spring.

The window is first moved to its lower position. This imparts more turnsto the spring and increases the torque therein. Thereafter by means of asuitable tool, such as a rod r shown in Figure 3, inserted through theslot m and a hole I in the clutch member I, the clutch members can bedisengaged. While still holding the clutch members disengaged the windowis raised, the increased torque being maintained and thereafter theclutch members are permitted to engage. Thus an increased torque isimparted to the spring. To further increase the torque the foregoingcycle of operations is repeated as often as may be required.

Should the torque of the spring be too great the window is first raised,thereby decreasing the torque. Thereafter the clutch members aredisengaged and while holding them in such position the window islowered. When the window is lowered the clutch members are permittedagain to engage, the spring then being at the decreased torque. Suchcycle of operations may be repeated as desired.

To lock the window the key k is pushed through the casing to fit betweenadjacent teeth of the pinion wheel g located therein.

If desired the spindle may be rotated by means of a suitable hand leveror power means and gearing to raise and lower the window.

What is claimed is:

In a vertically sliding window, balance mechanism therefore comprising atransverse spindle with helical scroll having a pitch which decreasesfrom one end to the other, means whereby said spindle is rotated byraising and lowering the window, a traveller member mounted on thespindle and co-operating with the scroll so that it will be movedlaterally when the spindle is rotated, a helical combined compressionand torsion spring encircling the spindle and anchored at one of itsends to the traveller member, a first clutch member fast on the spindleand a second clutch member to which the other end of the spring isanchored and which is held normally in driving engagement with the firstclutch member by means of said spring, the second clutch member beingcapable of axial displacement to disengage the clutch members by manualmeans and, when so displaced and held against rotation, the tension ofthe spring can be altered by raismg or lowering the window to rotate thespindle and the spring held in the tension to which it is altered bypermitting the clutch members to re-engage.

References Cited in the file of this patent UNITED STATES PATENTS

